1. Field of the Invention
The invention relates to a safety shield for a machining apparatus, more particularly to a safety shield that has a simple structure and permits easy access, and that greatly improves the safety of the working environment for a machining apparatus.
2. Description of the Related Art
Referring to FIG. 1, a conventional machining apparatus, such as a lathe, is shown to comprise a worktable 2 and a machining unit 1 mounted on the worktable 2. The machining unit 1 includes a plane stock 101, a lathe headstock 102, a tailstock 103, a cutter seat 104 and a numeric control device 105. The lathe headstock 102 is disposed at one end of the plane stock 101, whereas the tailstock 103 is disposed at the other end of the plane stock 101. The cutter seat 104 is mounted on the plane stock 101, and is movable in a longitudinal direction. The numeric control device 105 is mounted on an outer end of the tailstock 103. Hand wheels 106 are provided to control advancing and retreating movements of the cutter seat 104 during machining of a work piece (not shown) that is held between the headstock 102 and the tailstock 103.
The aforesaid conventional machining apparatus suffers from the following drawbacks: Through the digital control of the numeric control device 105 and the manual control of the hand wheels 106, a work piece can be tailored to achieve a designated shape via the movement of the cutter seat 104. Yet, as shown in FIG. 1, only a relatively small semicircular shield plate 107 is installed between the lathe headstock 102 and the tailstock 103 and is disposed near the lathe headstock 102 to prevent bits and pieces of the work piece from flying toward the operator. Apparently, the safety measure as such is not sufficient to provide adequate protection to the operator. Furthermore, no safety facility is provided to guard against injuries that can occur when the operator or other objects come into accidental contact with operating components of the lathe during a cutting operation. By the same token, other types of machining apparatus, such as planing machines, milling machines, grinding machines and drilling machines, are also susceptible to the same problems.
Therefore, the object of the present invention is to provide a safety shield for a machining apparatus to overcome the aforesaid drawbacks of the prior art.
Accordingly, the safety shield of the present invention is applied to a machining apparatus that includes a worktable and a machining unit mounted on the worktable. The safety shield comprises a shield frame, at least one curved shield member, and at least one curved sliding door.
The shield frame includes: a rectangular base adapted to be mounted on the worktable and having front and rear portions that extend in a longitudinal direction, and left and right portions that extend in a transverse direction, that interconnect the front and rear portions, and that cooperate with the front and rear portions to define an opening for permitting the machining unit to extend upwardly through the rectangular base; a pair of lateral plates extending upwardly from the rectangular base, each of the lateral plates having a base part disposed to extend in the transverse direction and connected to a respective one of the left and right portions of the rectangular base, and a top part opposite to the base part in an upright direction; a top beam disposed to extend in the longitudinal direction and having opposite ends connected to the top parts of the lateral plates, respectively; and a curved back plate having a top edge connected to the top beam, a bottom edge connected to the rear portion of the rectangular base, and a pair of curved lateral edges that interconnect the top and bottom edges and that are connected to the lateral plates, respectively.
Each shield member has a first curved lateral portion connected slidably to an adjacent one of the lateral plates so as to be slideable along a curved path between a first position, where the shield member extends between the top beam and the front portion of the rectangular base, and a second position, where the shield member extends between the top beam and the rear portion of the rectangular base and is disposed to overlap the back plate.
Each sliding door has an upper edge that is slidable along the top beam, and a lower edge that is slidable along the front portion of the rectangular base. The sliding door has a length in the longitudinal direction that is less than a length of the rectangular base in the longitudinal direction.
Since the safety shield of the present invention forms an enclosure for the machining unit of the machining apparatus, bits and pieces of a work piece can be retained inside the safety shield during operation of the machining unit. In addition, accidental contact by people or other objects with the operating components of the machining unit can be avoided. Thus, the safety of the working environment can be greatly enhanced.